Frank Skinner, Steve Coogan, Dylan Moran ... Doctor Brown? The prospect of this sexually charged clown act joining the rollcall of Edinburgh comedy award winners is a delicious one. And you wouldn't bet against it; he's among the favourites on the most interesting shortlist for years. It's both terrifying and titillating to be locked in a room with Doctor Brown for an hour. There's a real sense that anything could happen as the character – alter ego of American comic Phil Burgers – mimes, molests the audience and teases the boundaries of what constitutes silent comedy.

The subversion starts before we clap eyes on our host, with a wonderfully unexpected trick in which he contrives both to be on stage and off at the same time. This same routine signals the Doctor's marauding approach to the audience. Plenty of the laughs are of the appalled variety, as we watch one of our peers manhandled in the name of comedy. But Burgers' intentions are honourable – he wants us to loosen up and enjoy ourselves. And, particularly with a fantastic finale in which he directs a front-row stooge to re-enact the whole show, he's twisting audience participation into unimagined new shapes.

When he's not interacting, Burgers is on stage alone, dressed like an oriental wizard, silent, eyeing us up. He lets us see the process – of having nothing, then starting something that leads to a game, then to a hysterical scene: of two bulls flirting, then rutting; of Jesus trying to nail himself to the cross; of a cyclist demanding we supply his bell and horn sound effects. Burgers keep the whole show unstable: one minute he's an innocent child, winsomely seeking our approval; the next he's high-status and dangerous. Who knows what the mainstream would make of him? But his fringe show is both alarming and alluring.